W4_JTO_Ph2_Datacom_IT-part-10.pdf

JTO Phase II Data Network & IT MPLS-TP 10 MPLS-TP 10.1 Objective After reading this unit, you should be able to understand: Limitation of circuit switched network signal...

JTO Phase II Data Network & IT MPLS-TP 10 MPLS-TP 10.1 Objective After reading this unit, you should be able to understand: Limitation of circuit switched network signals. MPLS-TP Technology. Network Architecture of MPLS-TP. 10.2 Introduction The purpose of a transport network is to provide a reliable aggregation and transport infrastructure for any client traffic type. With the growth of packet-based services, operators are transforming their network infrastructures while looking at reducing capital and operational expenditures. In this context, a new technology is emerging: a transport profile of Multi-Protocol Label Switching called MPLS-TP. Transport network requirements of BSNL in the present scenario requires packet transportation, as all the new network elements are generating IP Traffic which is to be reliably transported. Based on this requirement, Packet Transport Network Planning guidelines have been prepared which outlines the basic concepts, technology & network architecture for the future transport network of BSNL. The network basically comprises of MPLS-TP based nodes.  In BSNL transport network was designed and deployed to carry basically TDM traffic comprising of Els, STM-1s & STM-16s. The network elements such as Switches, BTSs, BSCs& MSCs etc utilized TDM interfaces for transportation of information from one place to the other as part of service delivery. With the introduction of Broadband for which large number of DSLAMs were installed for high speed Broadband delivery, transport of Ethernet traffic was also introduced in BSNL network, through RPR Switches deployed in metro districts.  To carry TDM traffic efficiently & reliably SDH network comprising of STM-1 CPE, STM-1 ADM, STM-4, STM-16 ADM, STM-16 MADM and STM-64 has been extensively deployed which carried all type of TDM traffic. For long distance transport, linear DWDM systems ( 2.5G& 10G) were deployed which carried mostly SDH traffic through its lambdas ( STM-1, STM-4, STM-16). During 2009 Digital Cross Connect (DXCs) were also introduced in BSNL network with granularity of STM-1 Cross Connect along with aggregation and ASON capability. Thus SDH, DXC and DWDM is presently the backbone of the transport network of BSNL.  From 2006 onwards, with the advent of Ethernet over SDH (EoSDH) all SDH,DWDM& DXC Equipment procured by BSNL had the capability of transporting Ethernet traffic over SDH frame through Generic Framing Protocol (GFP) and Virtual Concatenation. This technology enabled BSNL to adapt to the transition phase in the technological development curve where the network elements were progressively switching towards Ethernet Interfaces ( FE, GE) but continued to support TDM interfaces too. Further with deployment of large JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 137 of 174 For Restricted Circulation JTO Phase II Data Network & IT MPLS-TP numbers of RPR Switches and OCLAN Switches with Broadband network the requirement of Ethernet transport through traditional TDM transport backbone was minimal.Even the routers of MPLS network (P&PE) had substantial TDM interfaces to enable the transportation of traffic in secure reliable media, utilizing BSNL's traditional TDM transport backbone.  But the situation depicted above is rapidly changing with 100% network elements being deployed by Mobile, Broadband and NGN for fixed access supporting only Ethernet interface for interconnection. Thus the volume of transport requirement for Ethernet Interfaces bas exponentially increased while requirement of TOM transport is rapidly vanishing. The network transportation requirement has clearly shifted from TOM with smaller portion of Packet to almost l00o/o Packet transport. As we move in the era of Packet transport, utilizing TDM network for the same becomes inefficient and costly. Moreover, the packet network gives support to different class of services, aggregation and dynamic statistical multiplexing etc. in transport layer for efficient delivery of services. 10.3 What is Packet Transport Network? Attributes required for Ethernet transport. Attributes Packet network Transport network Packet transport network Connection mode Connectionless Connection oriented Connection oriented OAM/Operation & Out of band In band In band maintenance Protection Control plane Data plane switching Data plane switching switching depend BW efficiency Statistical Fixed bandwidth Statistical multiplexing multiplexing Data rate Flexible Rigid SDH hierarchy Flexible granularity QoS QoS Single class QoS differentiation differentiation Packet Transport->Packet efficiency + Transport grade 10.4 MPLS-TP The goal of MPLS-TP is to provide connection-oriented transport for packet and TDM services over optical networks leveraging the widely deployed MPLS technology. Key to this effort is the definition and implementation of OAM and resiliency features to ensure the capabilities needed for carrier-grade transport networks – scalable operations, high availability, performance monitoring and multi-domain support. Objective of MPLS-TP is: JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 138 of 174 For Restricted Circulation JTO Phase II Data Network & IT MPLS-TP  To enable MPLS to be deployed in a transport network and operated in a similar manner to existing transport technologies (SDH/SONET/OTN)  To enable MPLS to support packet transport services with a similar degree of predictability, reliability, and OAM to that found in existing transport networks Current transport networks (e.g. SONET/SDH) are typically operated from a network operation center (NOC) using a centralized network management system (NMS) that communicates with the network elements (NEs) in the field via the telecommunications management network (TMN). The NMS provides well-known FCAPS management functions which are: fault, configuration, accounting, performance, and security management. Together with survivability functions such as protection and restoration, availability figures of >99,999% have been achieved thanks to the highly sophisticated OAM functions that are existing e.g. in SONET/SDH transport networks. This well proven network management paradigm has been taken as basis for the development of the new MPLS-TP packet transport network technology. Moreover, MPLS-TP provides dynamic provisioning of MPLS-TP transport paths via a control plane. The control plane is mainly used to provide restoration functions for improved network survivability in the presence of failures and it facilitates end-to-end path provisioning across network or operator domains. The operator has the choice to enable the control plane or to operate the network in a traditional way without control plane by means of an NMS. It shall be noted that the control plane does not make the NMS obsolete – the NMS needs to configure the control plane and also needs to interact with the control plane for connection management purposes. One of the major motivations for developing MPLS-TP was the need for the circuits in Packet Transport Networks. Traditionally packet transport switches each packet independently. However with connection oriented transport a ‗connection‘ is first setup between the end points and then all the traffic for that connection follows only that path through the network. This makes the Packet Transport Network very similar to the TDM networks and simplifies management and migration of the transport network. The concept of Label Switched Paths or LSPs from MPLS technology is already tried and tested and successful in the internetworking world. It made sense to adapt it for use in Packet Transport Networks. However there was a need to simplify the working of MPLS to make it more suitable for use in the Packet Transport World. With this in mind, some features were removed from the traditional MPLS, since it was felt that thesewere not needed in Transport World and would simply the network. The features from MPLS that arenot supported by MPLS-TP are: a) MPLS Control Plane: MPLS-TP does not require LDP or any other control plane protocol to set up the circuits. Instead a user provisioned model is followed. The user can provision a circuit from a centralized Network Management System in a way similar to TDM networks. b) Penultimate Hop Popping (PHP) : PHP is used by MPLS Edge Routers to reduce the load of two label lookups. However this causes problems with QoS and was disabled in MPLS-TP c) LSP Merge: Merging two LSPs (going to the same destination) reduces the number of labels being used in the network. However it makes it impossible to differentiate between traffic common from two different sources before the JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 139 of 174 For Restricted Circulation JTO Phase II Data Network & IT MPLS-TP merging happened. To simplify things in transport networks, LSP merge was also disabled. d) Equal Cost Multi Path: In traditional IP/MPLS networks different packets between a source-destination pair can take different paths. This is especially true when multiple equal cost paths exist. However this is in conflict with the concept of a circuit where all the traffic should follow the same path. Hence ECMP is disabled. 10.5 Differences between MPLS and MPLS-TP When it comes to the major differences between MPLS and MPLS-TP, here's what you need to know.  Bidirectional Label Switched Paths (LSPs). MPLS is based on the traditional IP routing paradigm -- traffic from A to B can flow over different paths than traffic from B to A. But transport networks commonly use bidirectional circuits, and MPLS-TP also mandates the support of bidirectional LSPs (a path through an MPLS network). In addition, MPLS-TP must support point-to-multipoint paths.  Management plane LSP setup. Paths across MPLS networks are set up with control-plane protocols (IP routing protocols or Resource Reservation Protocol (RSVP) for MPLS Traffic Engineering (MPLS-TE). MPLS-TP could use the same path setup mechanisms as MPLS (control plane-based LSP setup) or the traditional transport network approach where the paths are configured from the central network management system (management plane LSP setup).  Control plane is not mandatory. Going a step farther, MPLS-TP nodes should be able to work with no control plane, with paths across the network computed solely by the network management system and downloaded into the network elements.  Out-of-band management. MPLS nodes usually use in-band management or at least in-band exchange of control-plane messages. MPLS-TP network elements have to support out-of-band management over a dedicated management network (similar to the way some transport networks are managed today).  Total separation of management/control and data plane. Data forwarding within an MPLS-TP network element must continue even if its management or control plane fails. High-end routers provide similar functionality with non-stop forwarding, but this kind of functionality was never mandatory in traditional MPLS.  No IP in the forwarding plane. MPLS nodes usually run IP on all interfaces because they have to support the in-band exchange of control-plane messages. MPLS-TP network elements must be able to run without IP in the forwarding plane.  Explicit support of ring topologies. Many transport networks use ring topologies to reduce complexity. MPLS-TP thus includes mandatory support for numerous ring-specific mechanisms. JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 140 of 174 For Restricted Circulation JTO Phase II Data Network & IT MPLS-TP 10.6 MPLS and MPLS-TP Components As mentioned previously, MPLS refers to a suite of protocols, and MPLS-TP refers to a set of compatible enhancements to the MPLS protocol suite. These protocols and new enhancements can be separated into the following categories:  Network Architecture—Covers the definition of various functions and the interactions among them.  Data Plane-Covers the protocols and mechanisms that are used to forward the data packets. This can further be divided into the following subcategories: o Framing, forwarding, encapsulation o OAM o Resiliency (protection and restoration)  Control Plane—Covers the protocols and mechanisms used to set up the label- switched paths (LSPs) that are used to forward the data packets.  Management Plane—Covers the protocols and mechanisms that are used to manage the network. A list of protocols and mechanisms in each of these categories is provided in Figure 1. The figure also highlights the set of enhancements that are being pursued by MPLS-TP. The protocol and mechanisms highlighted in blue are being added to the MPLS/GMPLS protocol suite as part of the MPLS-TP effort. In Figure 1, the protocols and mechanisms highlighted in red might not be needed for the transport networks and are, therefore, being made optional. Note that these mechanisms will remain as part of the MPLS/GMPLS protocol suite. It is IETF‘s guidance to vendors that these mechanisms do not need to be supported on the platforms that are being targeted towards transport networks. JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 141 of 174 For Restricted Circulation JTO Phase II Data Network & IT MPLS-TP Figure 57: Components of MPLS and MPLS-TP 10.7 Applicability and Deployment Options for CPAN MPLS-TP enhancements are primarily applicable to the access and aggregation networks, where the majority of the migration from circuit-switched networks to packet- based networks is currently occurring, and where higher scale and lower cost is required. Juniper believes that the OAM enhancements to the MPLS protocol suite, however, will be extremely valuable to all MPLS networks, especially in the MPLS-based core networks. These OAM enhancements will allow service providers to have better visibility into their existing MPLS-based core networks, which will allow further optimization. The new OAM capabilities will also help the wholesale business by improving the tools required to measure and enforce strict SLAs. Juniper, therefore, is prioritizing the implementation of these OAM enhancements, such as the enhancements to BFD and LSP ping. Figure 2 illustrates how IP/MPLS and MPLS-TP can be deployed together and are very complementary in nature. JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 142 of 174 For Restricted Circulation JTO Phase II Data Network & IT MPLS-TP Figure 58: MPLS and MPLS-TP Deployment Options 10.8 BSNL Network Evolution: It is seen that BSNL requires immediate introduction of Packet Transport Network in order to provide reliable connectivity to the additional network elements and to meet the exponential growth in IP traffic. MPLS-TP enabled nodes with different configurations (as per the network requirement) maybe planned for transportation requirements in place of STM-1,16, 64 MADMs etc. where ever transport of packets is required. There is provision of carrying STM1 and E1 also in such devices. 10.8.1 Features:- 1. As these equipments are going to be used in place of SDH/TDM devices , which will be capable of servicing both TDM as well as packet (FE,GE etc.) clients, we need to have functionality similar to them and at the same time inefficiency of utilization of available bandwidth is to be minimized Hence for the user it should look like a SDH equipment. OAM (operation administration and maintenance) like SDH are available in these equipment. Some of them are:-  Point to point circuits can be provisioned.  The devices can be connected in ring /mesh.  End to end monitoring of each circuit is possible.  Protection 1 : 1(PW) or even 1 :n(LSP) can be provisioned.  It can transport synchronization information. 2. As switching in these devices are packet based ,it has features of packet based devices also. Some of these are:-  Point to multipoint or multipoint to multipoint circuits can be created.  Services can be provisioned at L1 or L2 layer.  QoS can be defined for individual customers. JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 143 of 174 For Restricted Circulation JTO Phase II Data Network & IT MPLS-TP 10.8.2 Proposed configuration of nodes:- Type-Al: (DC Powered Type) Uplink 1GE (optical) - 2 Downlink FE-4 FX-4 GE-2(Electrical) STM1-2 E1-8 Cross Connect Capacity - Minimum 5Gbps Type-A2: (AC Powered Type) Uplink - 1GE (optical) - 2 Downlink - FE-4 FX-4 GE-2(Electrical) STM1-2 E1-8 Cross Connect Capacity - Minimum 5Gbps Type-B1: Uplink - 10 GE( optical)- 2 Downlink - 1GE-16 (8Electrical+8 optical) FE -16 FX -16 STM1 -8 E1 -64 Cross Connect Capacity- 40 Gbps Type-B2: Uplink 10GE (optical) - 2 Downlink 10GE (optical) – 2 GE-32(16 Electrical + 16 Optical) FE-16 FX-16 STM1-8 E1-64 Cross connect capacity- 80 Gbps Type C: Uplink 40 GE(optical)-2 Downlink 10GE(optical)-12 FE/GE—64(32 optical + 32 electrical) (10/100/1000) JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 144 of 174 For Restricted Circulation JTO Phase II Data Network & IT MPLS-TP STM 1-8 E1-64 Cross connect capacity— 240 Gbps (Uplink- Line side,Downlink-Traffic side) 10.8.3 DISTANCE BETWEEN TWO NODES:- Type Al/A2 - 30 Km. TypeBl/B2 - 50 Km. Type C - 50 Km. 10.8.4 POWER SUPPLY:- Type Al /A2- AC Type or DC Type. Type Bl /B2- DC Type. Type C- DC Type. 10.9 Conclusion MPLS-TP is a set of enhancements to the already rich MPLS protocol suite. The current MPLS suite has successfully served packet-based networks for more than a decade. The MPLS-TP enhancements will increase the scope of MPLS overall, allowing it to serve both the transport and the services networks. The biggest and most important enhancements that are being developed under the MPLS-TP effort are OAM related (e.g., fault management and performance monitoring). These OAM enhancements will prove to be very valuable for the existing MPLS networks, as they will allow operators to improve the efficiency and effectiveness of their networks by enabling full end-to-end integration with the existing and the next-generation MPLS networks. JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 145 of 174 For Restricted Circulation